Explosively actuated tool



June 7, 1949. 1. R. MURPHY EXPLOSIVELY ACTUATED TOOL Filed Dec. 6. i944Snow 1 to:

Patented June 7, 1949 UNITED STATES EATENT FFICE (Granted under the actof March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 2 Claims.

The invention described and claimed herein may be manufactured and usedby or for the Government for governmental purposes, without payment tome of any royalty thereon.

This invention relates to tools actuated by explosive means and moreparticularly to apparatus of this character particularly adapted for usein penetrating hard surfaces, as, for example, hard soil or shale.

Equipment used heretofore in working soil preparatory to installingroads or placing poles has been found ineffective when the soil is veryhard. For example, earth augers are either ineffective or very slow whenemployed in hard soil and are not adapted for use by troops in fieldoperations.

It is the general object of this invention to provide an improvedexplosively actuated tool which is particularly adapted for boring holesin hard soil.

Another object of this invention is to provide a tool operated. by theforce of a detonating wave generated by an explosive charge to drive thetool into the ground which may thereafter be withdrawn from the soil,placed at another location, and readily reloaded.

Another object of this invention is to provide an explosively actuatedtool having a detonating chamber formed with a large upper portion and areduced lower portion, the large upper portion being provided with anopening adapted to admit a propellent charge and a mass of tampingmaterial to the chamber and release combustion gases therefrom, and thereduced lower portion being adapted to function as an expansion chamberfor the combustion gases.

Still another object of this invention is to provide an explosivelyactuated tool wherein the amount or density of the tamping material maybe varied to control the depth of pentration of the tool.

A further object of this invention is to provide an explosively actuatedtool including a drill point which is adapted to be detachably connectedselectively to either a starting drive rod or a driving rod leaving achamber at its free end to receive a propellent charge whereby thedrilling direction may be controlled.

A still further object of this invention is to provide an explosivelyactuated tool comprising a cup member adapted to receive a propellentcharge, a driving rod and a separable drill point wherein the drillpoint has a larger diameter than the driving rod to permit readywithdrawal of the rod from the body penetrated by the tool.

Other objects will be apparent from the following description of theinvention and the accompanying drawings in which:

Figure l is an elevational View with parts removed of an explosivelyactuated tool constructed in accordance with the principles of thisinvention;

Figure 2 is a longitudinal sectional view showing in enlarged detail theupper portion of the tool which contains the detonating chamber;

Figure 3 is a longitudinal sectional View showing in enlarged detail thelower portion of the tool with the drill point attached thereto;

Figure 4 is an elevational view showing an extension rod;

Figure 5 is an elevational view, partly in section, showing thepropellent charge for the tool; and

Figure 6 is an elevational view of a starting rod for setting the drillpoint in the body to be penetrated.

Referring to Figures 1, 2 and 3, the explosively actuated tool includesa drive rod IEI, provided at its uppermost end with a threaded portion Hand at its lowermost end with a reduced portion I2. The upper end of therod in has a flared portion ltd adjacent the threaded portion II whichprovides a horizontal face or shoulder. A cup member 13 having a taperedlower portion I4 provided with a longitudinal internally threaded recessI5 is adapted to engage the threaded portion 1 l of the drive rod Ill.The upper portion of the cup member I3 is provided with a longitudinalrecess l6 which is restricted near its lowermost portion to form ashoulder IT. A pair of diametrically opposed openings |8-l8 are formedin the walls of the cup member l3 which are adapted to receive adetachable handle 26. The handle 25, which may also be used as astarting tool as described below, enables the operator to rotate the cupmember 13 and engage or disengage the threaded portion of the recess I5and the threaded portion II of the drive rod Ill. The tapered portion M-of the cup l3 and the flared portion Illa, of the rod ID are complementary and thus, when the horizontal faces or shoulders of theseportions are in contact, the cup l3 and the rod I form an uninterruptedsubstantially conical surface. This arrangement enable the operator todetermine by inspection whether the cup member I3 and the drive rod [0are completely engaged. A separable drill point l9 having a cylindricalupper portion and conical pointed lower portion is provided with alongitudinal recess 20, which is adapted to receive the reduced portionl2 of the lowermost end of the drive rod Ill. The cylindrical upperportion of the drill point I9 is larger in cross section than the driverod l0 and thus drills an opening in the soil or other surface largerthan the rod I0 when forced therein by the latter.

The longitudinal recess 15 in the cup member 13 is adapted to receive apropellent charge shown in Figure 5, and thus forms a detonatingchamber. The propellent charge may consist of black powder or any othercommercially available explosive 2! and is employed in a container 22formed of light metal or: other waterproof material. The container 22which is preferably cylindrically shaped, is adapted to fit loosely inthe recess l with the peripheral edge of the bottom thereof resting onthe shoulder H. The top of the container 22 is provided with a frangibledisc 23 which may be perforated to permit a fuze 24 to be insertedthrough the opening and placed in the explosive 2i. When the propellentcharge container 22 is positioned in the recess 55 of the cup member :3,the restricted portion of the recess it below the shoulder ll forms anexpansion chamber for the combustion gases generated by the burningexplosive. The charge is exploded by igniting the fuze 24 and thedetonating wave generated moves downward in the detonating chamber,striking the bottom of the recess l6 and driving the cup member ifdownwardly. The cup member 53 transmits the explosive impact to thedrive rod IE3 through the shoulder formed by the flared portion 18a andin turn the separable drill point [9 is forced. into the soil. Unlessthe cup member 13 and the drive rod is are properly connected with thehorizontal face or shoulder of the tapered portion It in contact withthe horizontal face or shoulder of the flared portion lOa, the threadson the portion I I will be sheared by the impact of the explosion. Theoperator must therefore observe whether the complementary portions ofthe cup !3 and the rod l9 are engaged to provide the uninterruptedsubstantially conical surface described before igniting the fuze 24. Theforce of the detonating wave generated by the exploding charge exertedon the driving rod is may be controlled by covering the propellentcharge container 22 in the cup member [3 with tamping material 25 suchas sand, clay or other soil. The camping material 25 may be dropped intothe cup member 23 by gravity and, depending upon the amount and natureof the soil used, the driving rod Ii: will penetrate the soil with thedrill point E9 to a predetermined depth. If it is desired to force thedrivin rod it further into the ground, the tamping material may betamped in the cup member #3 thus increasing the density of the tamping.

The cup member l3 and the driving rod I0 secured thereto may bewithdrawn from the earth after penetration has been accomplished bydetonating the explosive material 2 i. Ordinarily this operation may becarried out easily since the drill point I9 is slightly larger than thedriving rod and the hole drilled by the point will not engage the rod l0tightly. If the force of the explosion causes the drive rod II) topenetrate the soil to too great a depth, the cup member I3 is disengagedfrom the threaded portion H, a tapped extension rod lflb, which is shownin Figure 4, secured to the threaded portion II and the drive rod thenwithdrawn from the soil. The drill point NJ is separated from drive rodHi When the latter is withdrawn and remains in the soil. The openingformed in the soil may be enlarged by inserting a prime cord chargetherein and exploding the charge.

In Figure 6, there is shown a combined starting drive rod and handle 26provided at its uppermost end with an enlarged head 21 and at itslowermost end with a reduced portion 28, The reduced portion 28 isadapted to fit into the recess 20 of the drill point 19. As describedabove, the rod 26 may be inserted in the openings |8I8 to provide ahandle for attaching the cup member 53 to the drive rod H]. Inoperation, as a starting tool, the reduced portion 28 is inserted in therecess 28 of the drill point 19 and force applied by strikin the head 21to drive the drill point into the soil, usually a depth of about onefoot. In this manner the drilling direction of the drill point Iii maybe controlled. Thus started, the tool 2G is withdrawn and the reducedportion l 2 of the drive rod H) is inserted in the recess 20 of the(hill point is. The cup member I3 is attached to the drive rod it, thepropellent charge with the fare 2 3 attached thereto inserted in therecess l6 and camping placed therein. The fuze 24 is ignited and theexplosive material 2| detonated forcing the tool into the soil. The toolmay then be withdrawn and inserted in another drill point at anotherlocation. If any difi'iculty is encountered in withdrawing the tool fromthe soil, a rod extractor or any other commercially available apparatussimilar to casing extractors employed in the oil industry may be used towithdraw the tool. The tool may thus be used to drill holes in extremelyhard soil rapidly, efiieiently and economically.

Having thus described my invention, what I claim as new and wish tosecure by Letters Patent is:

1. An explosively actuated earth boring tool comprising, in combination,a driving rod, the driving rod having opposite ends, one of which is areduced end, and a threaded portion on its opposite end, a drill pointremovably mounted on the reduced end of the driving rod, a cup memberthreadedly mounted on the threaded end portion of the dl'iVlng rod, thecup member being of substantially larger diameter than the driving rodand being adapted to receive a propellent charge and a mass of tampingmaterial, the cup member being provided with oppositely disposed holesadapted to receive a handle bar for attaching the cup member to thedriving rod, a handle bar in the holes, the said handle bar having areduced end portion adapted to fit into the drill point and an enlargedend portion adapted to form a driving head, whereby the said handle barmay be used interchangeably as a starting rod and as a handle bar, apropellant charge in the cup member, and means for igniting thepropellant charge.

An explosively actuated earth boring tool comprising, in combination, adriving rod, a drill point removably mounted on one end of the drivingrod, a cup member mounted on an opposite end of the driving rod, meansfor detachably mounting the cup member on the driving rod, a handleremovably mounted in the cup member for 2,472,120 5 6 attaching the cupmember to the driving rod, the REFERENCES CITED handle comprising a barhaving an end adapted to be received in the drill point and an enlargedg z fi g fii f i are of record m the driving end, whereby the handle maybe used inp terchangeably as a handle and as a startin rod, NITED STATESPATENTS the cup member being adapted to receive an ex- 5 Number NameDate plosive charge, the cup member having an open 49,362 Barnes Aug 155 end through which the expl v charge is 1,905,497 Peters Apr 25 1933ceived and a closed end attached to the driving 2,227,193 i t 1940 rod,and a shoulder on the inner wall of the cup member for retaining theexplosive charge and 10 for providing an expansion chamber for productsof combustion of the explosive charge.

IVESTER R. MURPHY.

